DE102022126331B3 - knife gate valve - Google Patents

Abstract

The invention relates to a knife gate valve with at least one movable gate valve. In order to create a knife gate valve that avoids the disadvantages of existing knife gate valves, the invention proposes a knife gate valve that has a pressure system that includes a guide tube and a pressure tube that can be displaced relative to one another , wherein the at least one slide plate can be pressed radially against the sealing seat via the pressure tube. The sealing surfaces are pressed directly in the area of the ring-shaped sealing part. This achieves a significantly better tightness in the closure.

Description

The invention relates to a gate valve with at least one movable gate valve.

Knife gate valves with one or two gate valves are used to shut off lines in industrial plants such as the chemical and petrochemical industry, smelting works and energy-producing companies.

• - Bei Einplattenschiebern, wie beispielsweise aus der DE 10 2017 108 576 A1 bekannt, erfolgt die Anpressung des Dichtsystems über eine definierte Anzahl an Federelementen, welche die Dichtringe permanent an die Schieberplatte andrücken oder mittels Abstimmblechen, welche zwischen Stutzen und Gehäuse eingebaut werden. Die Anzahl und Dicke der Abstimmbleche muß hierfür genau ermittelt werden, damit die Vorspannung so eingestellt werden kann, dass eine ausreichende Anpresskraft auf die Dichtringe bewirkt wird.
• - Bei Doppelplattenschiebern, wie beispielsweise aus der DE 10 2015 104 555 A1 , der DE 28 27 170 A1 oder der EP 0 326 787 A1 bekannt, erfolgt die Anpressung der Schieberplatten über ein mittig zwischen den Platten wirkendes Keil-in-Keil System welches über die Spindel bzw. Schieberstange in Eingriff gebracht wird und die Platten gegen die Dichtringe presst.

Single and double disc slides with different solutions for pressing and releasing the sealing elements are known from the prior art.

• - With Einplattenschieber, such as from the DE 10 2017 108 576 A1 known, the sealing system is pressed by a defined number of spring elements, which permanently press the sealing rings against the slide plate or by means of shims, which are installed between the connection piece and the body. The number and thickness of the shims must be determined precisely so that the preload can be adjusted so that sufficient contact pressure is exerted on the sealing rings.
• - With double plate slides, such as from the DE 10 2015 104 555 A1 , the DE 28 27 170 A1 or the EP 0 326 787 A1 known, the pressing of the slide plates takes place via a wedge-in-wedge system acting centrally between the plates, which is brought into engagement via the spindle or slide rod and presses the plates against the sealing rings.

Both solutions involve the following technical disadvantages.

When the spring action decreases, the spring elements no longer apply the required contact pressure to the sealing system and the slide valve begins to leak.

The distance between the sealing rings and the slide plate must be set with the greatest precision to ensure the function and tightness of the slide. Additional forces that act on the slide via the pipeline can lead to the valve blocking and the slide can no longer be actuated.

Likewise, temperature-related material expansions during operation often lead to blocking of the cover plate, making actuation more difficult or even impossible.

Due to the strong preload of the sealing system, high forces are required to actuate the slide. The drives must be dimensioned accordingly.

With the double knife gate valve, the plates are pressed against the sealing seats by a centrally acting wedge system.

• Um die Keilkräfte auf die gesamte Dichtfläche im Sitzbereich außerhalb des Zentrums des Schieberdurchganges zu übertragen, müssen die Platten sehr massiv ausgeführt bzw. in der Mitte massiv verstärkt werden, woraus ein hohes Gewicht der Platten resultiert.

This results in the following disadvantages:

• In order to transfer the wedge forces to the entire sealing surface in the seat area outside the center of the slide passage, the plates must be very solid or reinforced in the middle, which results in a high weight of the plates.

Since the contact pressure is applied centrally and not directly in the seating area of the sealing rings, the end plates can partially lift off when pressure is applied, which also leads to leaks.

The U.S. 2,664,918 A relates to a drain control seal. The drain control comprises a tubular body having a body having a platen chamber extending transversely of the body and having a platen and an elongate, radially disposed access passage. The seal has a clip slidably inserted into the inner end of the body to engage the panel. A screw means actuates the clamp relative to the body. The screw means includes an annular member located entirely within the body and screwed onto the clamp and having serrations on its outside between its end portions, two rolling bearing means spaced on the outside of the member and located at opposite end portions thereof and located at opposite end portions of the limb and supporting the limb in the body for rotation relative thereto. The member is operated by a gear.

The GB 171 082 A discloses a high pressure gate valve with parallel vapor tight surfaces. The gate valve is closed and opened by raising and lowering locking discs. For sealing, internally threaded nuts screwed onto bolts engage the threaded indentations of the locking washers so that counter rotation of these nuts moves the locking washers away from or towards each other. The lock washers are also connected to the parts that control axial displacement and raise and lower so that they are free to rotate independently of those parts.

The DE 270 221 A describes a gate valve. The gate valve includes closure plates which are capable of simultaneous longitudinal and rotary movement by engagement of a valve stem with teeth disposed on the back of the closure plates.

The GB 273 187 A relates to a sluice valve. The sluice valve has locking discs that can be pressed onto opposite valve seats by means of a screw-like gear.

The object of the present invention is to provide a knife gate valve which avoids the aforementioned disadvantages of existing knife gate valves.

According to the invention, this object is achieved by a flap slide that has a pressure system that includes a guide tube and a pressure tube that can be displaced relative to one another, with the at least one slide plate being able to be pressed radially against the sealing seat via the pressure tube, with an axially actuatable slide plate moving during the process non-rotating hollow spindle is provided, in the end of which a polygon is mounted in an axially sliding manner, on which a gear wheel is arranged, via which the guide tube can be rotated, the rotational movement of the guide tube being transferrable to the pressure tube, the polygon being a square or a hexagon .

The required contact pressure is applied precisely radially to the sealing surface via the guide tube and the pressure tube.

The sealing surfaces are pressed directly in the area of the ring-shaped sealing part. This achieves a significantly better tightness in the closure. Due to the possibility of moving the guide and pressure tube further beyond the previously defined end position and thus increasing the pressure force, a reliable seal with a purely metallic sealing seat can also be achieved for critical operating conditions at high temperature and high pressure. This also applies in the event of wear on the sealing surfaces.

The thickness of the slide plates is only to be designed according to the prevailing pressure and temperature conditions. As a result, it can be considerably thinner and lighter than existing knife gate valves.

An advantageous embodiment of the invention is that the pressure tube can be moved by rotating the guide tube.

It is also provided within the scope of the invention that a trapezoidal thread is provided to transmit the rotational movement of the guide tube to the pressure tube.

It is provided within the scope of the invention that the guide tube and the pressure tube are sealed off from one another by sealing means towards the interior of the slide.

Furthermore, it is advantageous that at least one protective plate is provided in order to prevent the medium from flowing directly onto the square and the gear wheel and the space between the slide plates.

• 1a, 1b, 1c, 1d und 1e zeigen einen erfindungsgemäßen Doppelplattenschieber in Seitenansicht, einen Schnitt A-A, eine Detailansicht B, einen Schnitt D-D und eine Detailansicht C.

An exemplary embodiment of the invention is described below with reference to drawings.

• 1a , 1b , 1c , 1d and 1e show a side view of a double disc valve according to the invention, a section AA, a detailed view B, a section DD and a detailed view C.

The knife gate valve comprises a housing (1) which is closed by a housing cover (3). A socket (2) connects to the housing (1). On the side of the socket (2) opposite the housing (1), there is a hood (4) to which a gear column (5) with a drive flange (6) is connected. A retaining bracket (9) for the handwheel drive is arranged on this drive flange (6) and carries the corresponding handwheel (32), which is secured by a clamping nut (34).

A hollow spindle (10) extends from the hand wheel (32) over the retaining bracket (9) and through the gear column (5) into the hood (4). In the lower end of the hollow spindle (10), a square (15) (or a hexagon) is mounted in an axially sliding manner, on which a gear (14) is mounted. A guide pipe (24) can be driven via a rotary movement of the spindle (10) and can transmit its rotary movement via a trapezoidal thread to a pressure pipe (23) on the slide plates (18).

The slide plates (18) are fastened to the lower end of the hollow spindle (10) via retaining lugs (19) and extend through the hood (4), the socket (2) and the housing (1).

The slide plate(s) (18) are/are moved from OPEN to CLOSED and vice versa via the axially actuated hollow spindle (10), which does not rotate during the process.

To press on and loosen the sealing system (sealing ring 20 and slide plate 18), the displaceable pressure tube (23) is moved in opposite directions by rotating the guide tube (24).

For this purpose, a rotary movement of the spindle (10) with the square (15) and the gear wheel (14) mounted on it drives the guide tube (24) by means of the counter-toothing engaging therein, which transfers its rotational movement to the pressure tube (23) by means of a trapezoidal thread and moves it in the axial direction until the set end position is reached and the slide plates (18) are pressed radially in the area of the sealing rings (20). The axially displaceable mounting of the pressure tube (23) allows simultaneous pressure in both directions and can therefore also be used for the variant with two end plates.

The guide tube (24) and pressure tube (23) are sealed from each other by packing rings (26 and 27) to prevent the medium from penetrating the trapezoidal thread of the guide tube (24) and pressure tube (23) and also to ensure trouble-free operation in heavily contaminated media.

The protective plates (21 and 22) prevent the medium from flowing directly onto the square (15) and the gear wheel (14) and the space between the slide plates (18) when the slide plates (18) are moved into the respective end position. Depending on the slider type, one or two protective plates (21 and 22) are fitted.

Reference List

1

Housing

2

Support

3

housing cover

4

Hood

5

pillar

6

drive flange

7

spindle nut

8th

retaining ring

9

mounting bracket

10

hollow spindle

11

collar bushing

12

packing gland

13

packing ring

14

gear

15

square

16

axle holder

17

traverse

18

slide plate

19

retaining tab

20

sealing ring

21

fender

22

fender

23

clamp tube

24

guiding scope

25

poetry

26

packing ring

27

packing ring

28

poetry

29

drive

30

gear coupling

31

gear cover

32

handwheel

33

handwheel

34

clamping nut

35

Adjusting spring

36

Adjusting spring

37

Sign

38

Sign

39

Press-release pointer

40

collar

41

washer

42

Screw

43

grub screw

44

logo

45

Hex bolt

46

Hex bolt

47

Hex bolt

48

Hex bolt

49

Hex bolt

50

Hex bolt

51

Hex bolt

52

Hex bolt

53

hex nut

Claims (5)

Knife gate valve with at least one movable slide plate (18), characterized in that the knife gate valve has a pressure system which comprises a guide tube (24) and a pressure tube (23) which can be displaced in relation to one another, the at least one slide plate via the pressure tube (23). (18) radially against the sealing seat can be pressed, an axially actuable hollow spindle (10) which does not rotate during movement being provided, in the end of which a polygon (15) is mounted in an axially sliding manner, on which a toothed wheel (14) is arranged, via which the guide tube (24) is rotatable, the rotational movement of the guide tube (24) being transferrable to the pressure tube (23), the polygon (15) being a square or a hexagon. Knife gate valve according to claim 1 , characterized in that the pressure tube (23) can be moved by rotating the guide tube (24). Knife gate valve according to one of Claims 1 until 2 , characterized in that a trapezoidal thread is provided to transmit the rotational movement of the guide tube (24) to the pressure tube (23). Knife gate valve according to one of Claims 1 until 3 , characterized in that the guide tube (24) and the pressure tube (23) are sealed by sealing means against each other towards the interior of the slide. Knife gate valve according to one of Claims 1 until 4 , characterized in that at least one protective plate (21, 22) is provided in order to prevent the direct flow of medium onto the square and the gear wheel (14) and the space between the slide plates (18).

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